The number of police officers at the London Marathon on Sunday will be boosted by 40 per cent in the wake of the Boston bombings, Met chiefs revealed today.

Several hundred more officers will be patrolling the capital’s streets to guard against any threat, Chief Superintendent Julia Pendry said.

More than 37,000 runners, including Olympic hero Mo Farah, are due to take part in the event. The 26-mile route, which is lined by hundreds of

thousands of spectators every year, starts in Blackheath and finishes near Buckingham Palace, passing some of the capital’s best known landmarks including Tower Bridge, Canary Wharf and Big Ben.

Ms Pendry said: “I have increased the number of officers for reassurance patrols by several hundred. It’s about making sure that people who come to London on Sunday feel safe when they are in the city.

“It is a good 40 per cent increase on last year on numbers of officers on the ground. We’ve got more search dogs out, we have got more on high-visibility patrols.”

Although she said there was nothing to connect the Boston atrocity with Sunday’s marathon, Ms Pendry added: “We’re in touch with the Americans all the time. At this time there is no link whatsoever between the Boston Marathon atrocities and the London Marathon on Sunday.

“What we have got is a number of contingencies. I have several

contingencies should anything change between now and Sunday; we can then react to anything that should happen. There is no link between the Boston Marathon and the London Marathon and there is no change to the threat level at this time to London.”

Members of the public coming to the capital are being asked to make sure that they keep their belongings with them to avoid sparking unnecessary security alerts.

Downing Street would not be drawn on the security implications. A spokesman said: “It is an operational matter for the police. They are well versed in securing major events.”

Croydon South MP Richard Ottaway, chairman of the Foreign Affairs Select Committee, said: “I’m confident the security services will make the right decisions.”